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Studies of Currents and Electric Fields in the Auroral Zone Ionosphere using Radar Auroral Backscatter

  • Raymond A. Greenwald
Part of the Astrophysics and Space Science Library book series (ASSL, volume 78)

Abstract

During the 1970s several advances have been made in the understanding of radar aurora. It has been shown that this phenomenon is due to the combined effects of the two-stream and gradient-drift plasma instabilities. These instabilities require relative streaming of the electrons and ions. Measurements at VHF frequencies have shown that the instabilities generally are excited when the streaming velocity is in excess of 300 to 400 m/s. At UHF frequencies streaming velocities in excess of 500 m/s appear to be required. Since radar aurora require electron-ion streaming, they are collocated with the auroral electrojets and many studies have used radar aurora to detect these currents. It has been found that the eastward electrojet generally is equatorward of the auroral arcs in the evening sector and that it is collocated with the region of downward field-aligned current. It has also been observed that the amplitude of signals backscattered from radar aurora is often proportional to the electrojet current density. Recent VHF studies have shown that Doppler data obtained from radar auroral backscatter can be used to measure the E-region electron drift velocity, the F-region plasma velocity, and the ionospheric electric field. This type of measurement is particularly valuable when it is made with dual auroral radar systems similar to STARE (Scandinavian Twin Auroral Radar Experiment). Over the past two years STARE has been used to study electric field patterns associated with electrojet and field-aligned currents, magnetospheric convection, the Harang discontinuity, Pc5 micropulsations, and the substorm expansion phase.

Keywords

Drift Velocity Electron Drift Auroral Zone Electron Drift Velocity Auroral Electrojet 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. Balsley, B.B.: 1967, J. Geophys. Res. 7, 2333.Google Scholar
  2. Balsley, B.B., W.L. Ecklund, and R.A. Greenwald: 1973, J. Geophys. Res. 78, 1681.ADSCrossRefGoogle Scholar
  3. Baumjohann, W., R.A. Greenwald, and F. Küppers: 1978, J. Geophys. Res., 44, 373.Google Scholar
  4. Brekke, A., R.T. Tsunoda, and M.J. Baron: 1977, Radio Sci., 12, 141.ADSCrossRefGoogle Scholar
  5. Buneman, O.: 1963, Phys. Rev. Lett., 10, 285.ADSCrossRefGoogle Scholar
  6. Cahill, L.T. Jr., R.A. Greenwald, and E. Nielsen: 1978, Geophys. Res. Lett., 5, 687.Google Scholar
  7. Cohen, R., and K.L. Bowles: 1967, J. Geophys. Res., 72, 885.ADSCrossRefGoogle Scholar
  8. Ecklund, W.L., D.A. Carter, J.G. Keys, and R.S. Unwin: 1974, J. Geophys. Res., 79, 3211.ADSCrossRefGoogle Scholar
  9. Ecklund, W.L., B.B. Balsley, and R.A. Greenwald: 1975, J. Geophys. Res. 80, 1805.ADSCrossRefGoogle Scholar
  10. Ecklund, W.L., B.B. Balsley, and D.A. Carter: 1977, J. Geophys. 82, 195.ADSCrossRefGoogle Scholar
  11. Farley, D.T.: 1963, J. Geophys. Res., 68, 6083.ADSMATHCrossRefGoogle Scholar
  12. Farley, D.T., and B.B. Balsley: 1973, J. Geophys. Res., 78, 227.ADSCrossRefGoogle Scholar
  13. Farley, D.T.: 1974, Rev. of Geophys. and Space Phys., 12, 285.ADSCrossRefGoogle Scholar
  14. Fremouw, E.J., and D.J. Fang: 1975, Radio Sci., 10, 891.ADSCrossRefGoogle Scholar
  15. Greenwald, R.A., W.L. Ecklund, and B.B. Balsley: 1973, J. Geophys. Res., 78, 8193.ADSCrossRefGoogle Scholar
  16. Greenwald, R.A.: 1974, J. Geophys. Res., 79, 4807.ADSCrossRefGoogle Scholar
  17. Greenwald, R.A., W.L. Ecklund, and B.B. Balsley: 1975a, J. Geophys. Res., 80, 131.ADSCrossRefGoogle Scholar
  18. Greenwald, R.A., W.L. Ecklund, and B.B. Balsley: 1975b, J. Geophys. Res., 80, 3635.ADSCrossRefGoogle Scholar
  19. Greenwald, R.A., and W.L. Ecklund: 1975, J. Geophys. Res., 80, 3642.ADSCrossRefGoogle Scholar
  20. Greenwald, R.A.: 1977, Dynamical and Chemical Coupling between the Neutral and Ionized Atmosphere, D. Reidel Publ. Co., Dordrecht-Holland, 291.Google Scholar
  21. Greenwald, R.A., W. Weiss, E. Nielsen, and N.R. Thomson: 1978, Radio Sci., in press.Google Scholar
  22. Gray, A.M., and W.L. Ecklund: 1974, NOAA Tech. Rep. ERL 306-AL9, National Oceanic and Atmos. Admin., Boulder, CO., USA.Google Scholar
  23. Hagfors, T., R.G. Johnson, and R.A. Powers: 1971, J. Geophys. Res., 76, 6093.ADSCrossRefGoogle Scholar
  24. Haldoupis, C., and G. Sofko: 1976, J. Geophys. Res., 54, 1571.Google Scholar
  25. Hughes, W.J.: 1974, Planet. Space Sci., 22, 1157.ADSCrossRefGoogle Scholar
  26. Kamide, Y., and A. Brekke: 1977, J. Geophys. Res., 82, 2851.ADSCrossRefGoogle Scholar
  27. Kisabeth, J.L., and G. Rostoker: 1977, Geophys. J.R. Astr. Soc., 49, 655.ADSGoogle Scholar
  28. Knox, F.B.: 1964, J. Atmos. Terr. Phys., 26, 239.ADSCrossRefGoogle Scholar
  29. Lee, K., C.F. Kennel, and F.V. Coroniti: 1974, J. Geophys. Res., 79, 249.ADSCrossRefGoogle Scholar
  30. Lui, A.T.Y., and C.D. Anger: 1973, Planet. Space Sci., 21, 799.ADSCrossRefGoogle Scholar
  31. Maeda, K., T. Tsuda, and H. Maeda: 1963, Rpt. Ionosph. space Res. Japan, 17, 147.Google Scholar
  32. Maurer, H., and B. Theile: 1978, J. Geophys., 44, 415.Google Scholar
  33. McDiarmid, D.R., and A.G. McNamara: 1978, J. Geophys. Res., 83, 3226.ADSCrossRefGoogle Scholar
  34. McDonald, B.E., T.P. Coffey, S. Ossakow, and R.N. Sudan: 1974, J. Geophys. Res., 79, 2551.ADSCrossRefGoogle Scholar
  35. Moorcroft, D.R.: 1978, Submitted to can. J. Phys.Google Scholar
  36. Moorcroft, D.R., and R.T. Tsunoda: 1978, in press, J. Geophys. Res.Google Scholar
  37. Nielsen, E., and R.A. Greenwald: 1978a, in press, J. Geophys. Res.Google Scholar
  38. Nielsen, E., and R.A. Greenwald: 1978b, Submitted to J. Geophys. Res.Google Scholar
  39. Ossakow, S.L., K. Papadopoulos, J. Orens, and T. Coffey: 1975, J. Geophys.-Res., 80, 141.ADSCrossRefGoogle Scholar
  40. Rino, C.L., V.B. Wickwar, P.M. Banks, S.-I. Akasofu, and E. Rieger: 1974, J. Geophys. Res., 79, 4669.ADSCrossRefGoogle Scholar
  41. Rogister, A., and N. D’Angelo: 1970, J. Geophys. Res., 75, 3879 ADSCrossRefGoogle Scholar
  42. Rogister, A.: 1971, J. Geophys. Res., 76, 7754.ADSCrossRefGoogle Scholar
  43. Schmidt, M.T., and S.P. Gary: 1973, J. Geophys. Res., 78, 8261.ADSCrossRefGoogle Scholar
  44. Siren, J.C., J.R. Doupnik, and W.L. Ecklund: 1977, J. Geophys. Res., 82, 3577.ADSCrossRefGoogle Scholar
  45. Sudan, R.N., J. Akinrimisi, and D.T. Farley: 1973, J. Geophys. Res., 78, 240.ADSCrossRefGoogle Scholar
  46. Sudan, R.N., and M. Keskinen: 1977, Phys. Rev. Lett., 38, 966.ADSCrossRefGoogle Scholar
  47. Tsunoda, R.T., R.I. Presnell, and R.L. Leadabrand: 1974, J. Geophys. Res., 79, 4709.ADSCrossRefGoogle Scholar
  48. Tsunoda, R.T.: 1975, J. Geophys. Res., 80, 4297.ADSCrossRefGoogle Scholar
  49. Tsunoda, R.T.: 1976, J. Geophys. Res., 81, 425.ADSCrossRefGoogle Scholar
  50. Tsunoda, R.T., and E.J. Fremouw: 1976a, J. Geophys. Res., 81, 6148.ADSCrossRefGoogle Scholar
  51. Tsunoda, R. T., and E.J. Fremouw: 1976b, J. Geophys. Res., 81, 6159.ADSCrossRefGoogle Scholar
  52. Tsunoda, R. T., and R.I. Presnell: 1976, J. Geophys. Res., 81, 88.ADSCrossRefGoogle Scholar
  53. Tsunoda, R.T., R.I. Presnell, Y. Kamide, and S.-I. Akasofu: 1976a, J. Geophys. Res., 81, 6005.ADSCrossRefGoogle Scholar
  54. Tsunoda, R.T., R.I. Presnell, and T.A. Potemra: 1976b, J. Geophys. Res., 81, 3791.ADSCrossRefGoogle Scholar
  55. Unwin, R.S.: 1966, J. Atmos. Terr. Phys., 28, 1183.Google Scholar
  56. Unwin, R.S., and J.G. Keys: 1975, J. Atmos. Terr. Phys., 12, 55.ADSCrossRefGoogle Scholar
  57. Walker, A.D.M., R.A. Greenwald, W.F. Stuart, and C.A. Green: 1978, Nature, 273, 646.ADSCrossRefGoogle Scholar
  58. Walker, A.D.M., R.A. Greenwald, W.F. Stuart, and C.A. Green: 1978, in press, J. Geophys. Res.Google Scholar
  59. Wang, T.N.C., and R.T. Tsunoda: 1975, J. Geophys. Res., 80, 2172.ADSCrossRefGoogle Scholar
  60. Winckler, J.R.: 1978, Chapman Conference on Magnetospheric Substorms and Related Plasma Processes, Los, Alamos.Google Scholar

Copyright information

© D. Reidel Publishing Company 1979

Authors and Affiliations

  • Raymond A. Greenwald
    • 1
  1. 1.Max-Planck-Institut für AeronomieKatlenburg-Lindau 3Germany

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